Reminiscent of the days after the Sept. 11, 2001, attacks, America is stunned by the senseless tragedy. Victims, friends, relatives, all of America and even people around the world are expressing shock and outrage that public safety was compromised by such a despicable act.

Police officers in SWAT gear carrying assault weapons are evidence of heightened security in Boston, and major public gatherings in other cities as well.

The uneasy atmosphere is a reality, as we try to return to normal, despite having more questions than answers. How could this happen to a 126-year-old tradition that attracts thousands of runners and supporters from around the globe?

As President Barack Obama said when he addressed the nation, the American resolve is strong and Boston will recover. A thousand law enforcement officers are investigating the case. The road to recovery is long and wide, but Boston and America are headed in that direction.

Diplomats and negotiators kept working Tuesday as a deadline approached to reach a deal on a framework agreement on Iran's nuclear program, but a U.S. State Department official said the discussion may continue after the cutoff.